scholarly journals Assessment of the applicability of a low-cost sensor–based methane monitoring system for continuous multi-channel sampling

2021 ◽  
Vol 193 (8) ◽  
Author(s):  
Isura Sumeda Priyadarshana Nagahage ◽  
Ekanayaka Achchillage Ayesha Dilruk Nagahage ◽  
Takeshi Fujino

AbstractSystems that are made of several low-cost gas sensors with automatic gas sampling may have the potential to serve as reliable fast methane analyzers. However, there is a lack of reports about such types of systems evaluated under field conditions. Here, we developed a continuous methane monitoring system with automated gas sampling unit using low-cost gas sensors, TGS 2611 and MQ-4, that use a simple cloud-based data acquisition platform. We verified the consistency, repeatability, and reproducibility of the data obtained by TGS 2611 and MQ-4 low-cost gas sensors by measuring high- and low-concentration methane samples. The normalized root-mean-square errors (NRMSEs) of the samples with high methane concentrations, [CH4] of 3, 4, 6, and 7%, were 0.0788, 0.0696, 0.1198, and 0.0719 for the TGS 2611 sensor, respectively, and were confirmed using a gas chromatograph as a reference analyzer. The NRMSEs of the samples with low [CH4] of 0.096, 0.145, 0.193, and 0.241% measured by the TGS 2611 sensor were 0.0641, 0.1749, 0.0157, and 0.1613, whereas those NRMSEs of the same concentrations measured by the MQ-4 sensor were 0.3143, 0.5766, 0.6301, and 0.6859, respectively. Laboratory-scale anaerobic digesters were tested using the developed system. The anaerobic digesters were continuously operated for 2 months, demonstrating the potential use of sensors for detecting and monitoring methane in the field level application. This study utilized a unique way to combine the advantages of low-cost sensors and develop a reliable monitoring system by minimizing drawbacks of low-cost sensors.

Sensors ◽  
2016 ◽  
Vol 16 (11) ◽  
pp. 1891 ◽  
Author(s):  
Toshio Itoh ◽  
Toshio Miwa ◽  
Akihiro Tsuruta ◽  
Takafumi Akamatsu ◽  
Noriya Izu ◽  
...  

Author(s):  
I Made Oka Widyantara ◽  
I Made Dwi Asana Putra ◽  
Ida Bagus Putu Adnyana

This paper intends to explain the development of Coastal Video Monitoring System (CoViMoS) with the main characteristics including low-cost and easy implementation. CoViMoS characteristics have been realized using the device IP camera for video image acquisition, and development of software applications with the main features including detection of shoreline and it changes are automatically. This capability was based on segmentation and classification techniques based on data mining. Detection of shoreline is done by segmenting a video image of the beach, to get a cluster of objects, namely land, sea and sky, using Self Organizing Map (SOM) algorithms. The mechanism of classification is done using K-Nearest Neighbor (K-NN) algorithms to provide the class labels to objects that have been generated on the segmentation process. Furthermore, the classification of land used as a reference object in the detection of costline. Implementation CoViMoS system for monitoring systems in Cucukan Beach, Gianyar regency, have shown that the developed system is able to detect the shoreline and its changes automatically.


2020 ◽  
pp. 1-1
Author(s):  
Abu Ilius Faisal ◽  
Sumit Majumder ◽  
Ryan Scott ◽  
Tapas Mondal ◽  
David Cowan ◽  
...  

Author(s):  
Nusrat Binta Nizam ◽  
Tohfatul Jinan ◽  
Wahida Binte Naz Aurthy ◽  
Md. Rakib Hossen ◽  
Jahid Ferdous

Landslides ◽  
2021 ◽  
Author(s):  
Lorenzo Brezzi ◽  
Alberto Bisson ◽  
Davide Pasa ◽  
Simonetta Cola

AbstractA large number of landslides occur in North-Eastern Italy during every rainy period due to the particular hydrogeological conditions of this area. Even if there are no casualties, the economic losses are often significant, and municipalities frequently do not have sufficient financial resources to repair the damage and stabilize all the unstable slopes. In this regard, the research for more economically sustainable solutions is a crucial challenge. Floating composite anchors are an innovative and low-cost technique set up for slope stabilization: it consists in the use of passive sub-horizontal reinforcements, obtained by coupling a traditional self-drilling bar with some tendons cemented inside it. This work concerns the application of this technique according to the observational method described within the Italian and European technical codes and mainly recommended for the design of geotechnical works, especially when performed in highly uncertain site conditions. The observational method prescribes designing an intervention and, at the same time, using a monitoring system in order to correct and adapt the project during realization of the works on the basis of new data acquired while on site. The case study is the landslide of Cischele, a medium landslide which occurred in 2010 after an exceptional heavy rainy period. In 2015, some floating composite anchors were installed to slow down the movement, even if, due to a limited budget, they were not enough to ensure the complete stabilization of the slope. Thanks to a monitoring system installed in the meantime, it is now possible to have a comparison between the site conditions before and after the intervention. This allows the evaluation of benefits achieved with the reinforcements and, at the same time, the assessment of additional improvements. Two stabilization scenarios are studied through an FE model: the first includes the stabilization system built in 2015, while the second evaluates a new solution proposed to further increase the slope stability.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Mayra K. S. Monteiro ◽  
Djalma R. Da Silva ◽  
Marco A. Quiroz ◽  
Vítor J. P. Vilar ◽  
Carlos A. Martínez-Huitle ◽  
...  

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 °C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5–1000 µM), with R2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.


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